[Ultrastructure of amitosis and mitosis of the liver]

Thousands of liver cells of several ultrastructural investigation programs of our laboratory have been evaluated in respect to amitosis and mitosis. Multiplication of hepatocytes by amitosis and mitosis often leads to bi-, tri- and multinucleated cells. No striking ultrastructural changes have been observed in the hepatocytes of human and animal livers. There are no indications of enhanced autophagocytosis or other signs of dedifferentiation. However, non-hepatocytes suffer ultrastructural changes during mitosis: endothelial cells reduce their organelles in number, round up their shape and form microvilli reaching between the microvilli of hepatocytic sinusoidal membrane. Mitotic Kupffer cells contain only small phagosomes and are separated from hepatocytes by endothelial cell processes.